﻿100 
  SANTA 
  MARIA 
  OIL 
  DISTRICT, 
  CALIFORNIA. 
  

  

  beds 
  underlying 
  the 
  area 
  is 
  a 
  northwestward-plunging 
  anticline 
  which 
  

   is 
  here 
  called 
  the 
  ,l 
  Ilarlncll." 
  There 
  is 
  both 
  surface 
  and 
  underground 
  

   evidence 
  of 
  its 
  presence, 
  but 
  its 
  exact 
  location 
  is, 
  of 
  course, 
  only 
  con- 
  

   jectural. 
  As 
  wall 
  be 
  noticed 
  on 
  examining 
  the 
  map 
  (PI. 
  X, 
  p. 
  92) 
  

   the 
  northern 
  flank 
  of 
  the 
  anticline 
  is 
  much 
  steeper 
  than 
  the 
  south- 
  

   western, 
  this 
  fact 
  apparently 
  having 
  a 
  direct 
  bearing 
  on 
  the 
  produc- 
  

   tiveness 
  of 
  the 
  wells 
  penetrating 
  this 
  flank. 
  

  

  GEOLOGY 
  OF 
  THE 
  WELLS. 
  

  

  The 
  surface 
  distribution 
  of 
  the 
  formations 
  in 
  the 
  immediate 
  vicinity 
  

   of 
  the 
  little 
  swale 
  on 
  the 
  ridge 
  in 
  which 
  Brookshire 
  wells 
  Nos. 
  3 
  and 
  4 
  

   are 
  situated 
  is 
  very 
  interesting. 
  The 
  bottom 
  of 
  the 
  swale 
  is 
  Monterey 
  

   (Miocene) 
  shale; 
  unconformably 
  overlying 
  this 
  on 
  the 
  south 
  is 
  fossil- 
  

   iferous 
  Fernando 
  (Pliocene) 
  sandstone 
  and 
  conglomerate; 
  immedi- 
  

   ately 
  north 
  of 
  the 
  swale 
  is 
  terrace-deposit 
  (Pleistocene) 
  sandstone. 
  

   (See 
  PL 
  XI, 
  B.) 
  It 
  has 
  been 
  suggested 
  that 
  such 
  a 
  condition 
  is 
  most 
  

   easily 
  explained 
  by 
  the 
  presence 
  of 
  a 
  fault 
  through 
  the 
  swale, 
  the 
  

   downthrow 
  being 
  on 
  the 
  north. 
  The 
  logs 
  of 
  the 
  wells 
  in 
  the 
  immediate 
  

   vicinity, 
  however, 
  offer 
  evidence 
  that 
  such 
  is 
  not 
  the 
  case, 
  but 
  that 
  

   the 
  underlying 
  Monterey 
  strata, 
  followed 
  almost 
  immediately 
  north 
  

   of 
  the 
  swale 
  by 
  fossiliferous 
  Fernando 
  beds, 
  plunge 
  steeply 
  north- 
  

   ward 
  and 
  are 
  overlain 
  unconformably 
  by 
  the 
  low-dipping 
  or 
  prac- 
  

   tically 
  horizontal 
  terrace 
  beds 
  which 
  are 
  exposed 
  on 
  the 
  ridge 
  north 
  

   of 
  the 
  swale. 
  Some 
  of 
  the 
  wells 
  starting 
  in 
  the 
  post-Monterey 
  forma- 
  

   tions 
  penetrate 
  sand 
  and 
  gravel 
  for 
  a 
  distance 
  of 
  more 
  than 
  600 
  feet 
  

   before 
  entering 
  the 
  Monterey. 
  Limestone, 
  probably 
  corresponding 
  

   to 
  the 
  limy 
  layers 
  associated 
  with 
  fossiliferous 
  beds 
  at 
  the 
  base 
  of 
  the 
  

   Fernando 
  in 
  the 
  railroad 
  cut 
  north 
  of 
  Schumann, 
  is 
  reported 
  as 
  occur- 
  

   ring 
  next 
  to 
  the 
  Monterey 
  shale 
  in 
  one 
  of 
  the 
  wells. 
  Water 
  is 
  encoun- 
  

   tered 
  in 
  gravel 
  at 
  various 
  horizons 
  in 
  the 
  Fernando 
  between 
  the 
  depths 
  

   of 
  150 
  and 
  600 
  feet. 
  Hartnell 
  well 
  No. 
  3 
  and 
  Brookshire 
  well 
  No. 
  1 
  

   (the 
  latter 
  about 
  half 
  a 
  mile 
  northeast 
  of 
  the 
  area 
  under 
  discussion), 
  

   which 
  penetrate 
  the 
  water-bearing 
  Fernando, 
  are 
  used 
  as 
  water 
  wells. 
  

   From 
  the 
  base 
  of 
  the 
  Fernando 
  to 
  their 
  bottoms 
  the 
  wells 
  penetrate 
  4 
  

   blue 
  and 
  brown 
  shale, 
  and 
  very 
  rarely 
  fine 
  sandy 
  layers. 
  "Shell" 
  

   strata, 
  many 
  of 
  them 
  underlain 
  by 
  gas 
  and 
  some 
  by 
  oil 
  and 
  gas, 
  are 
  

   encountered 
  here 
  and 
  there 
  throughout 
  the 
  shale. 
  

  

  The 
  first 
  oil 
  zone 
  (A) 
  occurs 
  about 
  400 
  feet 
  above 
  zone 
  B, 
  is 
  struck 
  

   at 
  depths 
  ranging 
  from 
  2,150 
  to 
  more 
  than 
  3,000 
  feet, 
  and 
  is 
  said 
  to 
  

   be 
  from 
  2 
  to 
  5 
  feet 
  thick. 
  On 
  examination 
  of 
  the 
  material 
  coining 
  

   from 
  this 
  and 
  the 
  underlying 
  productive 
  zones, 
  it 
  is 
  quite 
  apparent 
  

   that 
  the 
  oil 
  must 
  come 
  from 
  the 
  joint 
  cracks 
  or 
  interstices 
  between 
  

   the 
  fragments 
  of 
  more 
  or 
  less 
  fractured 
  shale, 
  as 
  no 
  true 
  sands 
  of 
  suffi- 
  

   cient 
  coarseness 
  to 
  allow 
  the 
  rapid 
  transmission 
  of 
  the 
  oil 
  have 
  been 
  

   encountered 
  in 
  the 
  productive 
  zones 
  in 
  the 
  wells 
  of 
  this 
  group. 
  

  

  